Cooking apparatus and method with product recognition

ABSTRACT

A method for controlling a clam grill that has first and second platens, said method comprising: moving said second platen toward said first platen; providing a signal in response to a detection of an impediment to the motion of said second platen; and stopping said second platen in response to said signal.

RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 11/146,685, filed on Jun. 7, 2005, which is acontinuation-in-part of U.S. patent application Ser. No. 11/070,348,filed on Mar. 2, 2005, which application claims the benefit of U.S.Provisional Patent Application Ser. No. 60/549,233, filed on Mar. 2,2004.

BACKGROUND

1. Field of the Disclosure

This disclosure relates to a cooking apparatus and method in which therelative motion of two platens is automatically controlled.

2. Discussion of the Background Art

Cooking apparatus that includes two surfaces generally cooks bycontacting opposed sides of a food product. Cooking apparatus of thistype has been used in a variety of cooker styles. For example, a clamgrill uses a lower platen and an upper platen that is moveable towardand away from the lower platen. Examples of clam grills are disclosed inU.S. Pat. Nos. 6,079,321 and Re 32,994. Another style is a toaster inwhich one surface is a platen and the other surface is a conveyor belt.The conveyor belt and the platen can be either horizontal, vertical orat an angle therebetween. Examples of toasters are disclosed in U.S.Pat. Nos. 6,201,218 and 6,281,478.

These known cooking apparatuses generally include a motion mechanismthat either manually or automatically moves one platen toward anotheruntil opposed sides of the food product are contacted by the platens.For example, the clam grill disclosed in U.S. Pat. No. 6,079,321automatically controls the motion based on a set of parameters that mustbe input to a controller for each type of food product. These parametersinclude a preset gap distance, which is the cooking distance between thetwo platens to accommodate food products of different thicknesses. Thesegap distances are set by manually inputting the preset gap distancesetting into the grill control and assigning the setting to a gap buttonon the user interface control along with a cooking time. This set ofcooking parameters (gap distance and cooking time) must be preselectedbefore placing the food product on the grill surface.

The clam grill operator must also input the type of food product beingcooked so that the controller uses the parameter set for that foodproduct. Should the operator inadvertently input the wrong type, theupper platen may not contact the food product or may put too muchpressure on the food product. Since the parameter set also includes thecook time for the food product type, the food product could beundercooked or over cooked. Thus, there is opportunity for human errorat the time of entry of the preset gap distances as well as at the timeof selecting the type of food being cooked.

There is a need for a cooking apparatus that automatically controls therelative motion of the two platens in a manner that avoids user error.

SUMMARY

The cooking apparatus of the present disclosure comprises a first platenand a second platen and a positioning mechanism that moves the secondplaten toward and/or away from the first platen. A detector is disposedto provide a signal in response to detection of an impediment to themotion of the second platen. A controller controls the positioningmechanism (a) to move the second platen toward the first platen and (b)to stop the second platen in response to the signal.

In one embodiment of the present disclosure, the impediment is the firstplaten and the signal is provided as the second platen makes contactwith the first platen.

In another embodiment of the present disclosure, the controller in apreheat mode further controls a heater to apply thermal energy to atleast one zone of the first platen and to the second platen.

In another embodiment of the present disclosure, the controller controlsthe positioning mechanism to maintain the second platen in contact withthe first platen until the zone of the first platen attains a firstpreset temperature and the second platen attains a second presettemperature.

In another embodiment of the present disclosure, the controller duringeach preheat mode records a position of the second platen attained as itis stopped by the positioning mechanism as a reference position, andwherein the controller uses the recorded reference position duringensuing cook cycles to recognize a thickness of a food product disposedon the first platen.

In another embodiment of the present disclosure, the impediment is anobject detected between a non-cooking position and a cooking position ofthe second platen. The controller further responds to the signal bycontrolling the positioning mechanism to move the second platen awayfrom the first platen to a non-cooking position.

In another embodiment of the present disclosure, one or more temperaturesensors are disposed to sense one or more temperatures at one or morelocations of the first platen. The impediment is a food product disposedon the first platen. The controller in a cook cycle uses the sensedtemperatures to evaluate an amount of food product on the first platensurface and compensates a cook time of the cook cycle based on theamount of food product.

In another embodiment of the present disclosure, the controllerdetermines the load sensitivity by evaluating a drop in the temperaturesand compensates the cook time based on the drop and a rate oftemperature recovery.

In another embodiment of the present disclosure, a temperature probe ismanually disposable at the locations on a surface of the first platenand that is removably connected in circuit with the controller; whereinthe controller calibrates surface temperature of the first platen basedon temperature probe signals received from the manually disposed surfacetemperature probes. The locations on the surface preferably bear visiblemarks.

The method of the present disclosure controls a clam grill that hasfirst and second platens by moving the second platen toward the firstplaten, providing a signal in response to a detection of an impedimentto the motion of the second platen, and stopping the second platen inresponse to the signal.

In another embodiment of the method of the present disclosure, theimpediment is the first platen and the signal is provided as the secondplaten makes contact with the first platen.

In another embodiment of the method of the present disclosure, in apreheat mode a heater is controlled to apply thermal energy to at leastone zone of the first platen and to the second platen.

In another embodiment of the method of the present disclosure, thesecond platen is maintained in contact with the first platen until thezone of the first platen attains a first preset temperature and thesecond platen attains a second preset temperature.

In another embodiment of the method of the present disclosure, themethod comprises the further steps of during each preheat mode recordinga position of the second platen attained as it is stopped as a referenceposition, and using the recorded reference position during ensuing cookcycles to recognize a thickness of a food product disposed on the firstplaten.

In another embodiment of the method of the present disclosure, theimpediment is an object detected between a non-cooking position and acooking position of the second platen. The second platen is then movedaway from the first platen in response to the signal.

In another embodiment of the method of the present disclosure, thesecond platen is moved to a non-cooking position.

In another embodiment of the method of the present disclosure, themethod further comprises the steps of sensing one or more temperaturesat one or more locations of the first platen. If the impediment is afood product disposed on the first platen; then the method uses thesensed temperatures to evaluate an amount of food product on the firstplaten and compensates a cook time of the cook cycle based on the amountof food product.

In another embodiment of the method of the present disclosure, themethod further comprises determining the load sensitivity by evaluatinga drop in the temperatures and compensating the cook time based on thedrop and a rate of temperature recovery.

In another embodiment of the method of the present disclosure, themethod further comprises sensing one or more temperatures at one or morelocations of the first platen, manually disposing a temperature probe atthe locations on a surface of the first platen; and calibrating surfacetemperature of the first platen based on temperature probe signalsreceived from the temperature probe.

In another embodiment of the method of the present disclosure, thelocations on the surface bear visible marks.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, advantages and features of the presentdisclosure will be understood by reference to the followingspecification in conjunction with the accompanying drawings, in whichlike reference characters denote like elements of structure and:

FIG. 1 is a perspective view of one embodiment of a two-surfaced cookingapparatus of the present disclosure;

FIG. 2 is a side view of the two-surfaced cooking apparatus of FIG. 1;

FIG. 3 is a rear view of the two-surfaced cooking apparatus of FIG. 1;

FIG. 4 is a top view of the upper platen assembly of the two-surfacedcooking apparatus of FIG. 1;

FIG. 5 is a cross-sectional view along line 5 of FIG. 4;

FIG. 6 is a view of detail B of FIG. 5;

FIG. 7 is a block diagram of an alternate embodiment of the detector ofthe two-surfaced cooking apparatus of the present disclosure;

FIG. 8 is a side view of a portion of the two-surfaced cooking apparatusof FIG. 1 that depicts another embodiment of the detector;

FIG. 9 is a side view of a portion of the two-surfaced cooking apparatusof FIG. 1 that depicts another embodiment of the detector;

FIG. 10 is a side view of a portion of the two-surfaced cookingapparatus of FIG. 1 that depicts another embodiment of the detector;

FIG. 11 is a side view of a portion of the two-surfaced cookingapparatus of FIG. 1 that depicts another embodiment of the detector;

FIG. 12 is a block diagram of a preferred embodiment of the controllerof the cooking apparatus of FIG. 1;

FIG. 13 is a flow diagram for the product recognition program of thecontroller of FIG. 12;

FIG. 14 is a flow diagram of another embodiment of a program that can beused with the cooking apparatus of FIG. 1;

FIG. 15 is a flow diagram of a safety program that can be used with thecooking apparatus of FIG. 1;

FIG. 16 depicts an auto-calibration set up for the cooking apparatus ofFIG. 1; and

FIG. 17 is a flow diagram of a load sensitivity program that can be usedwith the cooking apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is contemplated that the present disclosure can be used in variousstyles of two-surfaced cooking apparatus, for example, two-sided contacttoasting, clam grills and the like. However, by way of example andcompleteness of description, the present disclosure will be describedherein in a clam grill embodiment.

Referring to FIGS. 1-3, a two-surfaced cooking apparatus 20 of thepresent disclosure comprises a support structure 22 to which a lower(first) cooking platen 24 is horizontally mounted. Lower platen 24 has asmooth level cooking surface 26 on its upper side. Lower platen 24 isheated to cooking temperature by gas or electric means via heatingelements 28 or equivalent gas burners.

A platen assembly 30 and a platen assembly 31 are movably mounted to therear of support structure 22 by a positioning mechanism 40 and apositioning mechanism 41, respectively. As platen assembly 30 and platenassembly 31 are substantially identical, only platen assembly 30 will bedescribed in detail. Platen assembly 30 comprises an upper (second)cooking platen 32 that has a surface 34. Preferably, surface 34 isheated to cooking temperature by heating elements (not shown) mountedwithin a casing 36. Upper platen 32 is either smaller than orequivalently sized to lower cooking platen 24. A handle 38 mounted onthe front side of platen assembly 30 for manual manipulation thereof.Cooking apparatus 20 may have one or more upper platen assemblies.Although two upper platen assemblies are shown, other embodiments mayhave one or more than two upper platen assemblies. In a preferredembodiment, two or more separate upper platen assemblies are mountedover a single lower platen, allowing for greater flexibility for thecook/operator. Although lower platen 24 is shown as a single platen, itcan be two or more platens in alternate embodiments.

Cooking apparatus 20 further includes a controller 62 (shown in FIG. 2)that is interconnected with heaters 28, a motor controller 64, a userinterface 68 and one or two activation buttons 60. Controller 62controls the cook cycle of cooking apparatus 20 and in so doing controlsmotor controller 64 and positioning mechanism 40 that imparts motion toplaten assembly 30. User interface 68 includes a display and varioususer controls. Activation buttons 60 are disposed on the front ofcooking apparatus for user control of platen assembly 30. Activationbuttons 61 are disposed on the front of cooking apparatus for usercontrol of platen assembly 31.

As positioning mechanism 40 and positioning mechanism 41 aresubstantially identical, only positioning mechanism 40 will be describedin detail. Positioning mechanism 40 facilitates two distinct motions byplaten assembly 30 between an uppermost or non-cooking position (seeFIG. 3) to a cooking position. In FIGS. 1-3, platen assembly 30 is inthe non-cooking position and platen assembly 31 is in the cookingposition. In this embodiment, positioning mechanism 40 includes a linearactuator 42 that is linked to two vertical reciprocating shafts 44 by anactuator cross bar linkage 46. Actuator cross bar linkage 46 is clampedto vertical reciprocating shafts 44, which run through linear motionbearings 48. Vertical reciprocating shafts 44 are affixed to armpivot/stop heads 50. A cantilever beam 52 runs through arm pivot/stopheads 50 through rotational pivot bearings 54. When platen assembly 30is in its uppermost rotational position, linear actuator 42 is extendedto its maximum position, vertical reciprocating shafts 44 and armpivot/stop heads 50 are extended upward and to a position which forcesthe back end of cantilever beam 52 to contact rotational bearings 54. Inthis position, platen assembly 30 is at a predetermined angle in a rangeof about 45 degrees to about 60 degrees from the horizontal.

Positioning mechanism 40 further comprises a drive motor 56 and positionsensor switches 58 (FIG. 3). Drive motor 56 is interconnected with motorcontroller 64. A pulse encoder 66 is associated with motor 56 andprovides a pulse train to controller 62 when motor 56 is being driven.Position switches 58 are mounted on reciprocating shafts 44 to provideposition information to controller 62. In alternate embodiments,position switches 58 may be eliminated.

Prior to a cook cycle, platen assembly 30 is in its non-cookingposition. In response to user activation of activation buttons 60,controller 62 initiates a cook cycle by controlling motor controller 64to drive motor 56 to cause positioning mechanism 40 to move platenassembly 30 from the non-cooking position to a cooking position. Forexample, platen assembly 31 is shown in the cooking position.

Positioning mechanism 40 causes platen assembly 30 to descend bothvertically and through an arc caused by the cantilever weight of platenassembly 30 maintaining contact between rotational bearings 54 and theback of cantilever beam 52. When cantilever beam 52 and platen assembly30 become parallel with lower platen 24, the stop portion of armpivot/stop head 50 stops the rotational motion of cantilever beam 52causing purely vertical motion of platen assembly 30 from this point andfurther down toward surface 26 of lower platen 24. When upper platen 32makes contact with a food product 72, controller 62 responds by bringingupper platen 32 to an initial cooking position and initiating a cookprocedure. During the cook procedure upper platen 32 may be moved basedon the requirements of the cook procedure. For example, upper platen 32may be moved due to changed food product thickness (loss of grease orwater) or for applying more or less pressure to the food product atdifferent times during the cook procedure.

When the cook procedure is completed, controller 62 controls motorcontroller 64 to drive linear actuator 42 to move platen assembly 30vertically upward from the cooking position to the non-cooking position.The cantilever weight of upper platen 32 maintains contact between armpivot/stop head 50 until the back of cantilever beam 52 makes contactwith rotational pivot bearing 54. This movement ensures that platenassembly 30 is constantly parallel to lower platen 24 during this stageof upper platen travel. Once cantilever beam 52 makes contact withrotational pivot bearing 54 the vertical motion is changed to rotationalmotion to a point where platen assembly 30 is rotated through thepredetermined angle to the non-cooking position. Controller 60 causes anaudible signal to be sounded (e.g., about two seconds) prior to thestart of upward movement of platen assembly 30 to alert the operator ofimpending upper platen movement.

The present disclosure provides a detector that provides a triggersignal as upper platen 32 makes contact with food product 72. Controller62 responds to the trigger signal to control motor controller 64 tocause positioning mechanism 40 to bring upper platen 32 to the initialcooking position. At this time, controller 62 begins the cookingprocedure. The detector is shown herein in several differentembodiments.

Referring to FIGS. 4-6, a detector 70 is disposed or attached tocantilever beam 52 of positioning mechanism 40. When upper platen 32stops moving because it makes contact with a food product, its motioncomes to a stop or continues to move based on the cooking parametersinputted into controller 62. Positioning mechanism 40 continues to movecantilever beam 52 vertically downward toward casing 36. Detector 70senses a small change in the distance between cantilever beam 52 andcasing 36 to provide the trigger signal that triggers positioningmechanism 40 to bring upper platen 32 to the initial cooking position.

Referring to FIG. 6, a fastener 74 fastens cantilever beam 52 to casing36. Fastener 74 is mounted in cantilever beam 52 in a manner that allowsit to float vertically when upper platen 32 is in contact with foodproduct 72. Thus, when upper platen 32 makes contact with food product72, upper platen 32 stops but cantilever beam 52 continues downwardlydue to the floating action of fastener 74.

In this embodiment, detector 70 is preferably a proximity sensor, forexample, model PRX+4400, available from Hermetic Switch Inc. Detector 70may alternatively be a micro-switch, for example, model E47BM530,available from Eaton/Cutler Hammer.

Detector 70 may alternatively be a touch sensor including dielectricsensing as well as piezo-electric pressure sensing. For example, thetouch sensor may be model T107-A4E-073, available from Piezo Systems,Inc.

Detector 70 may alternatively be a sonar sensor that is attached toupper platen 32, lower platen 24 or support structure 22 to detect asound change due to upper platen 32 contacting the food product. Forexample, the sonar sensor may be model EFR-RTQB40KS, available fromPanasonic.

Although detector 70 is shown in a specific location, detector 70 can bepositioned at any suitable location of cantilever beam 52 that permitsdetection of upper platen 32 contacting food product 72. For example,these locations include the front, back, either side, middle or other.In an alternate embodiment, detector 70 may include multiple detectorspositioned at different locations.

Referring to FIG. 7, a detector 80 monitors the motor current of drivemotor 56. When upper platen 32 contacts food product 72, the motorcurrent changes. Detector 80 detects this current change and signalsmotor controller 64. Detector 80 can either be separate from motorcontroller 64 or integral with motor controller 64. If integral, thereis no need for detector 80 to signal motor controller 64. Detector 80includes a current sensing resistor 82 (or other circuit for measuringcurrent) connected in the motor current circuit. Detector 80 alsoincludes a current change detection circuit 84 that provides the triggersignal to motor controller 64 when current change detection circuit 84detects a change in motor current indicative of upper platen 32 makingcontact with food product 72. The trigger signal is supplied tocontroller 62.

Referring to FIG. 8, a detector 90 comprises a strain sensor attached ina location that detects a change in load after upper platen comeshorizontal and when the weight of upper platen 32 is reduced by restingon food product 72. When detector 90 detects this change in strain, itprovides a trigger signal to controller 62. Controller 62 then controlsmotor controller 64 to cause positioning mechanism 40 to bring upperplaten 32 to the cooking position. Like detector 80, detector 90 mayinclude a detection circuit (not shown) to detect when a change in themonitored strain signal is indicative of upper platen 32 making contactwith food product 72.

Referring to FIG. 9, a detector 100 includes an optical transmitter 102and an optical receiver 104 that are positioned to the rear and front,respectively, of cooking apparatus 20. Optical transmitter 102 providesan optical beam 106 from back to front at a level that will beinterrupted by upper platen 32 at about the time it contacts the foodproduct. Optical receiver 104 receives beam 106 and provides a triggersignal when upper platen 32 interrupts beam 106. Controller 62 uses thetrigger signal to bring upper platen 32 to the cooking position. Opticalbeam 106 may be visible light or invisible, e.g., infrared.

Referring to FIG. 10, alternatively an optical detector 110 is mountedto cantilever beam 52. Thus, an optical transmitter 112 and an opticalreceiver 114 are mounted and spaced from one another by a gap such thata light beam emitted by optical transmitter 112 traverses the gap and isreceived by optical receiver 114. A shutter 116 is mounted on casing 36.When upper platen 32 is not in contact with the food product, shutter116 is outside the gap between optical transmitter 112 and opticalreceiver 114. When upper platen 32 slows or stops, it contacts the foodproduct, while cantilever beam 52 continues to move toward casing 36such that shutter 116 enters the gap and interrupts the light beam.Optical receiver 114 responds by providing a trigger signal tocontroller 62. Controller 62 uses the trigger signal to bring upperplaten 32 to the cooking position.

Referring to FIG. 11, a detector 120 comprises a plurality oftemperature sensors 122 disposed at various locations in upper platen32. Temperature sensors 122 provide temperature signals to controller62. When the operator starts a cooking cycle, controller 62 monitors thetemperature sensor signals. When controller 62, based on the temperaturesensor signals, determines that a given temperature drop in a specifiedamount of time has occurred, it controls motor controller 64 to causepositioning mechanism 40 to bring upper platen 32 to the cookingposition.

It will be apparent to those skilled in the art that detection circuitscan be used in any of the detectors 70, 80, 90, 100, 110 and 120 todiscriminate the trigger signal from noise.

Referring to FIG. 12, controller 62 includes a processor 130interconnected by a bus 136 with an input/output (I/O) module 132 and amemory 134. Memory 134 may be any suitable memory that includes, randomaccess memory (RAM), read only memory (ROM), flash or other memory typesor any combination thereof. Processor 130 may be any suitable processorthat is capable of running programs that execute cook cycles includingcook procedures. I/O module 132, contains interfaces to each of aplurality of input/output devices, including user interface 68, pulseencoder 66, detector 70, 80, 90, 100, 110 or 120, heater elements 28,motor controller 64 and any other input/output devices included in acooking apparatus.

Memory 134 stores a plurality of programs and parameter data including acook cycle program 140, a product thickness list 144, a set of cookprocedures 146 and a distance counter 148. Cook procedures 146 include aset of cook procedures for use by cooking apparatus 20. For example,cook procedures 146 include a cook procedure for bacon, a cook procedurefor a hamburger, a cook procedure for a chicken patty and so on.

A cook procedure, for example, may simply be a cook time or may alsoinclude temperatures for different portions of the cook time, differentpressures and/or gap distances for upper platen at different portions ofthe cook time.

Cook cycle program 140 includes a product recognition program 142 thatrecognizes a food product 72 currently on the grill surface 26 of lowerplaten 24 of FIGS. 1-6. This recognition is based on a travel distanceof upper platen 32 measured between a reference point to a position atwhich it makes contact with food product 72. When cooking apparatus 20is first started from a cold start, a preheat mode is used before foodproduct 72 can be placed on lower platen 24. In the preheat mode, platenassembly 30 is lowered until it comes to a stop on lower platen 24 andengages detector 70. The heaters for lower platen 24 and upper platen 32are turned on and the platen surfaces are heated to their presettemperatures. This procedure has the advantage of saving energyvis-a-vis a procedure in which lower platen 24 and upper platen are outof contact with one another during the preheat mode.

After upper platen 32 has been preheated, platen assembly 30 is raisedto its upper most non-cooking position to allow the operator to safelyplace food product 72 on lower platen 24. As platen assembly 30 beginsto rise, cantilever beam 52 reaches the end of the float distance,detector 70 is released from its detected state and generates a triggersignal that controller 62 uses as the reference point. This referencepoint represents a reference count value, e.g., zero, of surface 26 oflower platen 24.

As platen assembly 30 continues to rise, encoder pulses are counted fromthe reference point to the non-cooking position. Controller 62 recordsthe total count value from the reference point to the upper mostnon-cooking position, which represents a predetermined reference countvalue. After food product 72 is placed on lower platen 24, platenassembly 30 is again lowered. When upper platen 32 contacts food product72, detector 70 generates a trigger signal, which controller 62 uses torecord the encoder pulse count value at the time of contact with foodproduct 72. The product thickness is represented by the differencebetween the pulse count value at the food product contact time and thepredetermined reference count value.

It will be apparent to those skilled in the art that other techniques ofmeasuring the travel distance can be used. For example, the traveldistance can be measured by the time that elapses between currenttriggered count value and the reference point value. The elapsed time,for example, is measured by counting pulses from a timing source, suchas a clock. This elapsed time or pulse count is recorded in distancecounter 148. Product recognition program 142 uses distance to recognizea product thickness and uses the recognized product thickness to selecta product cook procedure from cook procedures 146 that matches theproduct thickness.

The above described procedure of establishing a zero reference value ofsurface 26 of lower platen 24 provides a self-calibration every time apreheat mode is performed, e.g., upon each power up of cooking apparatus20. This is in contrast to systems in which calibration is performedonly at time of installation or service. These systems are subject todrift that can affect the calibration. For example, the drift might bedue to component wear and/or aging, equipment abuse and/or changes intemperature, barometric pressure and/or humidity.

Referring to FIG. 13, cook cycle program 140 begins at step 170 bystarting a cook cycle. Step 170 is performed in response to the operatoractivating activation button 60. At step 172 cooking apparatus 20 isinitialized. For example, heating elements 28 are turned on and otherpreliminary operations (not germane to the present disclosure) areperformed. Once cooking apparatus 20 is initialized, product recognitionprogram 142 is executed.

At step 174, distance counter 148 is initialized to a reference value,e.g., zero. At step 176 motor 56 is started. Processor 130 provides oneor more command signals via I/O module 132 to motor controller 64 toprovide drive current to motor 56. This causes positioning mechanism 40to lower upper platen 32 from its non-cooking position. At step 178,there is a determination of whether a trigger signal has been receivedfrom the detector (70, 80, 110, 110 or 120). If not, at step 180 it isdetermined if an encoder pulse has been received. If not, controlreturns to step 178. If step 180 determines that an encoder pulse hasbeen received, at step 182 distance counter 148 is incremented. It willbe appreciated by those skilled in the art that distance counter 148could also be decremented from the reference value. Control then returnsto step 178 and steps 178, 180 and 182 iterate until step 178 detects atrigger signal.

If step 178 determines that a trigger pulse has arrived, at step 184 aproduct cook procedure is selected from cook procedures 146 based on thecount value of distance counter 148 as of the arrival of the triggerpulse. At step 186 the selected cook program is executed. When step 186is completed at step 188 upper platen 32 is returned to its non-cookingposition. To perform step 188, processor 130 provides one or morecommand signals via I/O module 132 to motor controller 64 to providedrive current to motor 56. This causes positioning mechanism 40 to raiseupper platen 32 from its cooking position to its non-cooking position.

More specifically, step 184 matches the trigger count value of distancecounter 148 with count values for different product thicknesses for thefood products stored in product thickness list 144. That is, each countvalue stored in product thickness list 144 is indicative of acorresponding product thickness of the food product of a correspondingcook procedure. If the trigger count value of distance counter 148 isin-between two of the count values in product thickness list 144, thecount value closest to the trigger count value is used to select acorresponding cook procedure from cook procedures 146.

In an alternate embodiment, product thickness list 144 stores athickness window for the product of each cook procedure. The thicknesswindow is defined by an upper and a lower count value plus or minus atolerance. The thickness window within which the trigger count valuefalls is used to select the corresponding cook procedure from cookprocedures 146. If the trigger count value falls between two thicknesswindows, the closest thickness window is used. For example, thepredetermined thickness could be 0.500±0.060 inch.

During a programming operation, product thickness list 144 and productcook procedures 146 are populated with respective thickness count valuesand cook procedures for the food products that are to be cooked withfood cooking apparatus 20. The thickness count values and cookprocedures can be entered, for example, via a keyboard or other inputdevice (not shown) either via a wired connection or a wireless link.

Referring to FIG. 9, an alternate embodiment of the cook cycle programresponds to the trigger signal to execute a cook procedure that ispre-selected by the operator, for example, from user interface 68. Acook cycle program 200 begins at step 202 by starting a cook cycle. Step202 is performed in response to the operator activating activationbutton 60. At step 204 cooking apparatus 20 is initialized. For example,heating elements 28 are turned on and other preliminary operations (notgermane to the present disclosure) are performed.

At step 206 motor 56 is started. Processor 130 provides one or morecommand signals via I/O module 132 to motor controller 64 to providedrive current to motor 56. This causes positioning mechanism 40 to lowerupper platen 32 from its non-cooking position. At step 208, there is adetermination of whether a trigger signal has been received from thedetector (70, 80, 110, 110 or 120). If not, then step 208 repeats. Ifstep 208 determines that a trigger signal has been received, then atstep 208 the pre-selected cook procedure is executed. When thepre-selected cook procedure has been completed, then at step 212 upperplaten 32 is returned to its non-cooking position. Processor 130provides one or more command signals via I/O module 132 to motorcontroller 64 to provide drive current to motor 56. This causespositioning mechanism 40 to raise upper platen 32 from its cookingposition to its non-cooking position.

Referring to FIG. 15, a safety feature program 300 is operative duringthe descent of upper platen 32 from the non-cooking position towardlower platen 24 to return upper platen to the non-cooking positionshould an obstruction or impediment be detected as upper platen 32descends. The obstruction, for example, might be a body part of theoperator, such as an arm or a hand, or a physical object other than foodproduct 72, such as a pot, pan or other object. The presence of theobjection is determined by controller 62 based on an input or triggersignal from detector 70.

When a cooking process is initiated, upper platen 32 moves downwardtoward lower platen 24. If at any time between the uppermost ornon-cooking position and a predetermined distance above cooking surface26, controller 62 receives a trigger signal from a detector, controller62 stops upper platen 32, reverses its direction of motion and returnsit to the uppermost position. The predetermined distance is greater thanthe food products being cooked. For example, the predetermined distancein one embodiment was set at 1.375 inch. The detector, for example, canbe any of the detectors 70, 80, 90, 100 or any other suitable detector.For the purpose of the following description, the detector is assumed tobe detector 70.

Safety feature program 300 is executed by controller 62 and at step 302determines if a cooking process is being performed. If no, program 300waits for a cooking process to start. If yes, at step 304, controller 62determines if there is a trigger signal from detector 70. If no, steps302 and 304 are repeated until a trigger signal is determined by step304. If yes, at step 306 controller 62 determines if the current countis greater than a predetermined value that represents the predetermineddistance above cooking surface 26. That is, the trigger signal hasoccurred above food product 72 and, therefore, was generated by anobstruction. If yes, controller 62 at step 308 stops the downward travelof upper platen 32 and moves it upward until it is returned to theuppermost position.

Should step 306 determine that the current count value is not greaterthan the predetermined value, controller 62 proceeds to perform the cookprocess at step 310. At step 312, controller 62 returns upper platen 32to its uppermost position when the cook process is finished.

Referring to FIG. 16, a zone of lower platen 24 comprises a mark X thatdenotes the location of a temperature probe 320 affixed to or insertedin a probe receptacle of a lower surface 27 of platen 24. Temperatureprobe 320 is connected to controller 62 via an electrical connection322.

A feature of the present disclosure provides for automatic temperaturecalibration of surface 24 without having a person manually input thetemperature values. Controller 62 is provided with a temperaturecalibration mode that is selectable, for example, by an operator usinguser interface 68. When the temperature calibration mode is selected,the operator places a temperature probe 326 near or in the vicinity of(e.g., over) the mark X that corresponds to the location of temperatureprobe 320. Although only one temperature probe 320 is shown, it shouldbe apparent to those skilled in the art that one or more temperatureprobes 320 can be deployed at various locations of lower platen 24. Eachsuch temperature probe 320 would be identified by a correspondingvisible mark X.

The operator also plugs into controller 62 an electrical connection 324that is connected to temperature probe 326. Controller 62 comparestemperature values of surface 26 sensed by temperature probe 326 totemperature values received from temperature probes 320 and matches thevalue from the remote temperature probe 326 automatically calibratingtemperature probes 320 without any manual inputs of temperature valuesinto user interface 68. For example, controller 62 compares thetemperatures sensed by temperature probe 326 with the temperaturessensed by corresponding temperature probes 320. Controller 62 uses thedifference between the two temperatures as an offset value to determinesurface temperature based on actual sensed temperature by temperatureprobe 320.

The present disclosure also comprises a load sensitivity feature thatenables controller 62 to evaluate a temperature profile of a cookingcycle and, from this profile, determine the amount of food product 72being cooked, and adjusting cooking time based on the amount of foodproduct 72 on the grill surface 26. In one embodiment. The loadsensitivity is rated in three categories, namely, a light load thatrequires a minimum cook time, a medium load that requires a nominaltime, and a full load that requires a maximum time. As an example, theoperator places one food product (e.g., a hamburger patty) 72 on lowergrill surface 26 and initiates a cooking cycle by pressing acorresponding activation button 60 or 61. Upper platen 32 lowers untilit contacts food product 72. When food product 72 is contacted, upperplaten 32 stops and the lift mechanism continues downward slightlytripping a switch (detector 70, 80, 110 or 120) indicating upper platen32 has stopped on food product 72. Controller 62 then determines thefood product thickness and initiates a cooking cycle timer based on theproduct thickness. As food product 72 is being cooked the temperaturesof surface 26 of the grill platen 24 and the surface 34 of upper platen32 will drop due to the food product being colder than surfaces 26 and34. As the surface temperatures drop, controller 62 monitors thetemperature drop and recovery rate over time of surfaces 26 and/or 34during the cooking process. Just prior to end of the cooking cycle,controller 62 determines the rate and amount of surface(s) temperaturedrop and rate of recovery. Using this data, controller 62 determinesthat there is a light load on the grill and shortens the cook timeslightly so that food product 72 is not over cooked.

If the operator had placed the maximum amount of food products 72 on thegrill surface and started a cooking cycle, the “temperature curve” ofthe grilling surfaces would drop further and recover at a slower rate.Near the end of the cooking cycle, controller 62 would evaluate thisdata, and extend the cooking time to compensate for the reduced thermalinput to the full load of food products 72.

If a number of food products greater than one and less than a full loadare placed on lower grill surface 26 and a cooking cycle is initiated,controller 62 will monitor a “temperature curve” for temperature dropand recovery rate.

Referring to FIG. 17, a load sensitivity program 350 is executed bycontroller 62. At step 352, a cook cycle timer is initiated based onthickness of the food product to a default or nominal time for therecognized food product. At step 354, controller 62 runs the cookprocess for the food product. At step 356, controller 62 determines ifthe current cook cycle timer value is equal to a predetermined loaddetermination time. This predetermined time is preferably near the endof the default time. If no, steps 354 and 356 repeat until step 356determines that the current cycle timer value equals the predeterminedload determination time. If yes, at step 358, controller 62 determines aload sensitivity (light, heavy or in between) based on temperature dropand rate of recovery of surfaces 26 and/or 34 of lower and upper platens24 and 32. If light, the default time is reset to a predeterminedminimum time at step 360. If heavy, the default timer is reset to amaximum predetermined time at step 362. If in between, the default timeis maintained at step 364. The predetermined minimum and maximum timescan be determined by running cook cycles for the food products andrecording cook cycle times for light, heavy and in between loads.

It will be apparent to those skilled in the art that the assignment ofthe default or nominal time to the in between time is a matter of choiceand could alternatively be assigned to either the light or heavy loadsensitivities with adjustments to the program procedure. Also, the loadsensitivities could be rated in more or less than three categories ifdesired.

The present disclosure having been thus described with particularreference to the preferred forms thereof, it will be obvious thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of the present disclosure as defined in theappended claims.

1. A method for controlling a clam grill that has first and second platens, said method comprising: moving said second platen toward said first platen; providing a signal in response to a detection of an impediment to the motion of said second platen; and stopping said second platen in response to said signal.
 2. The method of claim 1, wherein said impediment is said first platen and said signal is provided as said second platen makes contact with said first platen.
 3. The method of claim 2, further comprising in a preheat mode controlling a heater to apply thermal energy to at least one zone of said first platen and to said second platen.
 4. The method of claim 3, further comprising maintaining said second platen in contact with said first platen until said zone of said first platen attains a first preset temperature and said second platen attains a second preset temperature.
 5. The method of claim 3, further comprising during each preheat mode recording a position of said second platen attained as it is stopped as a reference position, and using said recorded reference position during ensuing cook cycles to recognize a thickness of a food product disposed on said first platen.
 6. The method of claim 1, wherein said impediment is an object detected between a non-cooking position and a cooking position of said second platen; and further comprising moving said second platen away from said first platen in response to said signal.
 7. The method of claim 16 wherein said second platen is moved to a non-cooking position.
 8. The method of claim 1, further comprising sensing one or more temperatures at one or more locations of said first platen; wherein said impediment is a food product disposed on said first platen; using said sensed temperatures to evaluate an amount of food product on said first platen and compensating a cook time of said cook cycle based on said amount of food product.
 9. The method of claim 8, further comprising determining said load sensitivity by evaluating a drop in said temperatures and compensating said cook time based on said drop and a rate of temperature recovery.
 10. The method of claim 1, further comprising sensing one or more temperatures at one or more locations of said first platen, manually disposing a temperature probe at said locations on a surface of said first platen; and calibrating surface temperature of the first platen based on temperature probe signals received from the temperature probe.
 11. The method of claim 10, wherein said locations on said surface bear visible marks. 